|Acrion’s CO2 Wash system. Click to enlarge.|
FirmGreen Energy (FGE) has begun construction of a landfill gas (LFG) clean-up project near Grove City, Ohio at the Franklin County landfill, operated by the Solid Waste Authority of Central Ohio (SWACO). (Earlier post.)
When fully operational this summer, FGE’s Bio-Fuels facility will generate 250 kW of renewable electricity for use in the landfill gas cleanup process. In addition, the project will produce compressed natural gas (CNG) fuel for use by SWACO’s truck fleet.
The CNG fuel will displace up to one thousand gallons of diesel daily. FGE’s Bio-Fuels facility will significantly reduce SWACO’s energy consumption, emissions, and fleet operating costs, according to the company.
The core of the process is Acrion Technologies’ CO2 Wash; FirmGreen is a licensee of the Acrion process.
Landfill gas is a natural product of the biological decomposition of organic waste. The resulting gas has a variety of chemical components, but at most sites the two principal components are methane (CH4) and CO2, with much smaller amounts of hydrogen sulfides (H2S), inerts and volatile organic compounds (VOCs).
A big problem with LFG projects is the presence of trace components. Typical LFG contains heavy hydrocarbons (both aliphatic and aromatics such as benzene) as well as numerous chlorinated hydrocarbons. These trace compounds are in some cases toxic or hazardous and also cause rapid failure or engine and turbine components. There are now federal statutes which cover landfill emissions.
The CO2 Wash process removes contaminants from LFG using liquid carbon dioxide obtained directly from the LFG, and produces a stream of contaminant-free methane and CO2.
The unit being installed in Ohio will clean up to 300 standard cubic feet per minute (scfm) of raw landfill gas. FirmGreen plans to market larger units by the end of 2007.